Thank you Cheung,
may the farce be with you...too !
I keeped the secret as you see. . happy some of my ideas was kept !
thank you for all your work by mail with Pedja.
So the Positivists project is born !
- Here firstly, we have two solutions for impact maximum of TDA 1541 lovers : A little TDA1541 boards to come for fanatic DIY : input and output stages and PS choosed by each diyer but with a good reference for the LAYOUT around the TDA1541 coreboard. Firstly RyanJ board may come soonly, secondly more we hope : Set3up (no news yet) and maybe Vano (nos news yet).
- secondlyt: a very good neutral design maid by a music lover in the presonn of Pedja with the Famous AYA 2 with a SOTA Layout and very good critics from reviewers (lovers of classical music for instance). Thanks to Pedja Rodric at Audial to follow us !
With the second you are sure to have a musical solution, better than "Good enough" !
may the farce be with you...too ! I keeped the secret as you see.
. happy some of my ideas was kept !thank you for all your work by mail with Pedja.
So the Positivists project is born !
- Here firstly, we have two solutions for impact maximum of TDA 1541 lovers : A little TDA1541 boards to come for fanatic DIY : input and output stages and PS choosed by each diyer but with a good reference for the LAYOUT around the TDA1541 coreboard. Firstly RyanJ board may come soonly, secondly more we hope : Set3up (no news yet) and maybe Vano (nos news yet).
- secondlyt: a very good neutral design maid by a music lover in the presonn of Pedja with the Famous AYA 2 with a SOTA Layout and very good critics from reviewers (lovers of classical music for instance). Thanks to Pedja Rodric at Audial to follow us !
With the second you are sure to have a musical solution, better than "Good enough" !
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TDA1541A core board group buy/interest list
Hey all,
Just want to get an idea of the amount of people interested in my TDA1541A core board.
http://www.diyaudio.com/forums/digital-line-level/256084-group-buy-interest-list-tda1541a-core-board.html#post3921851
Leave your name and amount of boards required.
Cheers!
Hey all,
Just want to get an idea of the amount of people interested in my TDA1541A core board.
http://www.diyaudio.com/forums/digital-line-level/256084-group-buy-interest-list-tda1541a-core-board.html#post3921851
Leave your name and amount of boards required.
Cheers!
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Hey Ryan,
Looking forward to your board..
Would like to ask a question about;
-Bypass cap pads on AOL and AOR to prevent RF from entering output stage. [47nf - depending on output impedance]
This is something I've been wondering about and have trouble understanding, maybe you or someone else can help me make sense of it..
I've seen the feedback resistor on opamp stages bypassed by some capacitance which apparently creates a low pass filter. Also, some tube based stages bypass the I/V resistor. Seems that the cap//resistor forms a frequency dependant voltage divider.
I've seen other ccts that use 2.2nF across the 1541A outputs, and additionally R//C in the I/V stage.
Any comment much appreciated.
Shane
Looking forward to your board..
Would like to ask a question about;
-Bypass cap pads on AOL and AOR to prevent RF from entering output stage. [47nf - depending on output impedance]
This is something I've been wondering about and have trouble understanding, maybe you or someone else can help me make sense of it..
I've seen the feedback resistor on opamp stages bypassed by some capacitance which apparently creates a low pass filter. Also, some tube based stages bypass the I/V resistor. Seems that the cap//resistor forms a frequency dependant voltage divider.
I've seen other ccts that use 2.2nF across the 1541A outputs, and additionally R//C in the I/V stage.
Any comment much appreciated.
Shane
Hi Shane, i'm looking forward to it as well, should be much better than my current setup.
This cap will serve as a low pass filter. At the value of 47nF it will shunt 400khz+ to ground depending on your output impedance.
Hope that helps, someone else may have a more detailed response to share.
Cheers! time for a beer!
Hi RyanJ,
Hope your board will born as we need a little minimalist coreboard to work around alone AND to improve it around all together (step by step with collaborative : complete PS, good layout for a stacked outboard or more seriously a crystal board stacked with two vias near the dac chip.
My idea to allow THE CRYSTAL BOARD to be closer with the chip than with uf.l connector for I2S input is to have two VIAS for feed the chip : one signal vias near the pin clock, for example a vias on the last smd resistor trace pad in front of the pin concerned by the clock. the other vias for gnd close to the first of course as all RF signal as to be very close with a little coax cable of 75 ohms or 50 ohms (the impedance of the boards). The good news is than the Dgnd and clock pin are on the same left side of the TDA !
for this futur and so on... the final price has to be low, with e.g. some chineese plateform Abraxalito showed in TDA1545 thread opened by Audiolapdance: you can draw and print the final project with low cost (don't know about the quality but Braxie is known to be serious). No more than ten euros imho. Maybe a little more if uf.l already soldered with SOTA pratices)
It will be great to have two possibilities to improve the initial "Is there any TDA1541 good kit?" ("enough" or SOTA).
With you here : http://www.diyaudio.com/forums/digi...up-buy-interest-list-tda1541a-core-board.html (and after with others boards)
And from Pedja Rodric here : http://www.diyaudio.com/forums/group-buys/256068-gb-aya-ii-tda1541a-dac-2014-edition-pcb-kit.html
After all it is a mutual sucees with a collaborative work behind !
Hope your board will born as we need a little minimalist coreboard to work around alone AND to improve it around all together (step by step with collaborative : complete PS, good layout for a stacked outboard or more seriously a crystal board stacked with two vias near the dac chip.
My idea to allow THE CRYSTAL BOARD to be closer with the chip than with uf.l connector for I2S input is to have two VIAS for feed the chip : one signal vias near the pin clock, for example a vias on the last smd resistor trace pad in front of the pin concerned by the clock. the other vias for gnd close to the first of course as all RF signal as to be very close with a little coax cable of 75 ohms or 50 ohms (the impedance of the boards). The good news is than the Dgnd and clock pin are on the same left side of the TDA !
for this futur and so on... the final price has to be low, with e.g. some chineese plateform Abraxalito showed in TDA1545 thread opened by Audiolapdance: you can draw and print the final project with low cost (don't know about the quality but Braxie is known to be serious). No more than ten euros imho. Maybe a little more if uf.l already soldered with SOTA pratices)
It will be great to have two possibilities to improve the initial "Is there any TDA1541 good kit?" ("enough" or SOTA).
With you here : http://www.diyaudio.com/forums/digi...up-buy-interest-list-tda1541a-core-board.html (and after with others boards)
And from Pedja Rodric here : http://www.diyaudio.com/forums/group-buys/256068-gb-aya-ii-tda1541a-dac-2014-edition-pcb-kit.html
After all it is a mutual sucees with a collaborative work behind !
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Thanks, Ryan.
The output impedance that forms a filter with the shunt 47nF would be the output impedance of the 1541A itself?. That makes sense.. any idea if its a fixed value or what it depends on? (it doesn't appear to be on the data sheet either).
Shane
Hi Shane,
This value will depend on the load impedance. If you have around 10 ohm the value of 47uF should be pretty good at shunting the 400khz+ frequencies without rolling off the trebles. If you have a lower input impedance you will need a higher value cap. For example if you have half the input impedance, 5 ohms, then you will need a value of 100nF. Although its arranged in a CR not RC configuration so not sure if its calculated the same way.
Low pass calculator
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Thanks, Ryan..
Ah, ok.. so its the input impedance of whatever is across the 1541A output. So 39R//10nF has about the same 400kHz corner.
400kHz for Non-os or are you using 4x OS?
Regards,
Shane
Hey Shane
At the moment i don't have any cap in this exact position, I have it much closer to my output stage but i cant remember the value. Im running at 44.1k. Im not convinced digital filtering is the way to go as yet. But i could be persuaded, just a matter of looking into it...
If your oversampling 44.1k material, it may not be as critical to have a cap there anyway (less RF energy).
At the moment i don't have any cap in this exact position, I have it much closer to my output stage but i cant remember the value. Im running at 44.1k. Im not convinced digital filtering is the way to go as yet. But i could be persuaded, just a matter of looking into it...
If your oversampling 44.1k material, it may not be as critical to have a cap there anyway (less RF energy).
Thanks mate.. reason I asked if you were using oversampling is that with non-os, it seems the 'image' (alias?, ultrasonic?) frequencies appear at
http://www.audiokarma.org/forums/archive/index.php/t-552972.html
Since there is no oversampling of the digital samples, the sampling frequency stays at 44.1kHz (or whatever else it might be). This means that the "image" frequency components will be created at each of (N*44.1kHz +/- 20kHz), with N = 1, 2, 3, ...
So, we will have image frequency components at:
44.1 - 20 = 24.1kHz
44.1 + 20 = 64.1kHz
2*44.1 - 20 = 68.2kHz
2*44.1 + 20 = 108.2kHz
I wonder in reality how much of a big deal it is, theres a lot of contradictory info out there. You might be right about up sampling to a high frequency and benefit of shifting this alias ultrasonic thing right up to ~192kHz, RC filter set at 100kHz to attenuate quite well at (192kHz- 20 =) 172kHz and hopefully not molest phase at 20k.
Or, something like that… at least its a plan.
http://www.audiokarma.org/forums/archive/index.php/t-552972.html
Since there is no oversampling of the digital samples, the sampling frequency stays at 44.1kHz (or whatever else it might be). This means that the "image" frequency components will be created at each of (N*44.1kHz +/- 20kHz), with N = 1, 2, 3, ...
So, we will have image frequency components at:
44.1 - 20 = 24.1kHz
44.1 + 20 = 64.1kHz
2*44.1 - 20 = 68.2kHz
2*44.1 + 20 = 108.2kHz
I wonder in reality how much of a big deal it is, theres a lot of contradictory info out there. You might be right about up sampling to a high frequency and benefit of shifting this alias ultrasonic thing right up to ~192kHz, RC filter set at 100kHz to attenuate quite well at (192kHz- 20 =) 172kHz and hopefully not molest phase at 20k.
Or, something like that… at least its a plan.
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Member
Joined 2006
Hi,
Funny I had the same idea with this Bufer because the inductor.
Say to work better with a Wima FKP2 cap shunt of few pico instead of the smd one (hint of Gary fellow in an another thread and another DAC)
But I surmise the cap of the board to color the result also... i have a limited trust to the panasonic FM caps of the board !
I believe also than the work of Abraxalito about passive filter network after the DAC is promising like the one Bernhard fellow maid some years ago.
Here in Europe in Solid State used, a little Lundhal transformer woerth its 60 euros also to avoid the cap with any lake of bass energy or clearness but with a relax treble....
Funny I had the same idea with this Bufer because the inductor.
Say to work better with a Wima FKP2 cap shunt of few pico instead of the smd one (hint of Gary fellow in an another thread and another DAC)
But I surmise the cap of the board to color the result also... i have a limited trust to the panasonic FM caps of the board !
I believe also than the work of Abraxalito about passive filter network after the DAC is promising like the one Bernhard fellow maid some years ago.
Here in Europe in Solid State used, a little Lundhal transformer woerth its 60 euros also to avoid the cap with any lake of bass energy or clearness but with a relax treble....
Member
Joined 2006
6moons audio reviews: Zanden Audio Model 5000 MkII
Look at what filters Zanden Dac has Eldam.
These are the ones you want?
Look at what filters Zanden Dac has Eldam.
These are the ones you want?
ahahah;;; They are biased at six moons ! Reviews with the Cirrus chip like one of the best of the world ... lol !
I need to find a job before sponsoring the hifi brands again... these days, IT manager jobs are rare in my country... Trusting crisis + economic crisis...
They are beginner at Zanden with the filter ! look at what Bernahard fellow made here with its 20 x PCM56 ! and it's huge passive fiilter !
I need to find a job before sponsoring the hifi brands again... these days, IT manager jobs are rare in my country... Trusting crisis + economic crisis...
They are beginner at Zanden with the filter ! look at what Bernahard fellow made here with its 20 x PCM56 ! and it's huge passive fiilter !
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Pedja is a kind man : "this project would be slightly updated on this occasion, to facilitate its use with possibly different external front ends, DEM clocking schemes, etc."
from Audial site AYA2 project page !
I support also Ryan for a minimalist coreboard... two different DIY path... that's good !
from Audial site AYA2 project page !
I support also Ryan for a minimalist coreboard... two different DIY path... that's good !
Pedja Rogic will modified the one shot edition AYA2 2014 PCB & kit for us with the followings :
"
1. More versatile input connectivity
I2S line will get U.FL connectors. Since AYA II inputs are switched exactly at this line, adding these connectors will make it really versatile. So, apart from two existing front ends, you can use AYA II D/A section with one or two external sources. Mind you, I generally do not recommend “modular approach”, because it usually brings dubious benefits at the expense of obvious, even critical compromises layout-wise. However, I am aware that adaptive USB audio class 1 device is kinda surpassed these days and, since I do not plan to offer neither asynchronous USB nor audio class 2 USB device in DIY shape (nor do I have any major further plans regarding DIY items for that matter, sorry), it is also the way to “open” this project in that direction. Yet, AYA II could still sound nicely with existing USB stage, as well.
2. Synchronous DEM clocking
Instead of typically used capacitor to enable free running internal TDA1541A DEM oscillator, you can synchronize its DEM circuit to the incoming master or bit, or even word clock. Everything that is needed will be on-board, and this includes binary counter with selection of dividing ratios, and proper interface to TDA1541A pins 16 and 17. To make DEM working this way, you have to take into account the frequency you are actually starting with, and to connect adequately scaled frequency to DEM.
3. TDA1541A mode selection
This version will have a switch at pin 27 to facilitate possible TDA1541A use in simultaneous data mode.
Also, I do not really recommend using any other output stage, but TDA1541A current output will have its own set of clearly marked pads"
Thanks to him
"
1. More versatile input connectivity
I2S line will get U.FL connectors. Since AYA II inputs are switched exactly at this line, adding these connectors will make it really versatile. So, apart from two existing front ends, you can use AYA II D/A section with one or two external sources. Mind you, I generally do not recommend “modular approach”, because it usually brings dubious benefits at the expense of obvious, even critical compromises layout-wise. However, I am aware that adaptive USB audio class 1 device is kinda surpassed these days and, since I do not plan to offer neither asynchronous USB nor audio class 2 USB device in DIY shape (nor do I have any major further plans regarding DIY items for that matter, sorry), it is also the way to “open” this project in that direction. Yet, AYA II could still sound nicely with existing USB stage, as well.
2. Synchronous DEM clocking
Instead of typically used capacitor to enable free running internal TDA1541A DEM oscillator, you can synchronize its DEM circuit to the incoming master or bit, or even word clock. Everything that is needed will be on-board, and this includes binary counter with selection of dividing ratios, and proper interface to TDA1541A pins 16 and 17. To make DEM working this way, you have to take into account the frequency you are actually starting with, and to connect adequately scaled frequency to DEM.
3. TDA1541A mode selection
This version will have a switch at pin 27 to facilitate possible TDA1541A use in simultaneous data mode.
Also, I do not really recommend using any other output stage, but TDA1541A current output will have its own set of clearly marked pads"
Thanks to him
Member
Joined 2006
Yeap agree Shane, I will go with the both pcbs myself.
I writed early than every tweaker need a reference for its own work and thinked the reason Vader OP could be involved was because he had a AMR CD777 : a very good ref (I hope SET3UP had the opportunity to check his board with him.
For me It will be I hope the AYA2 with the optimised BOM parts of Pedja as a ref and as it is an hobby I will make fanatic tweak with the RynaJ or others coreboard pcb ! We have a double hobby : listen to music and iron soldeR AND WITH TWO PCBS I can do the both in same time like I did with the excellent Subbu V3 !
regards to all
I writed early than every tweaker need a reference for its own work and thinked the reason Vader OP could be involved was because he had a AMR CD777 : a very good ref (I hope SET3UP had the opportunity to check his board with him.
For me It will be I hope the AYA2 with the optimised BOM parts of Pedja as a ref and as it is an hobby I will make fanatic tweak with the RynaJ or others coreboard pcb ! We have a double hobby : listen to music and iron soldeR AND WITH TWO PCBS I can do the both in same time like I did with the excellent Subbu V3 !
regards to all
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